The quartz sleeve separates the ultraviolet lamp from the water while passing UV-C into it. Length and diameter both identify a sleeve, and this catalogue stocks several at similar lengths — order against the reactor model rather than against a measurement of the old part alone. This is the 1630 mm sleeve for the Wedeco Rex. The matching 65 W 4-pin lamp is stocked under item 1349-0307 and the Rex electronic ballast under item 13233-1015. Wedeco was founded in Herford, Germany in 1976 and is now a Xylem brand.